Electrically heated sauna installation



1967 v. K. KETOLA ELECTRICALLY HEATED SAUNA INSTALLATION 2 Sheets-Sheet1 Filed Jan. 22, 1964 INVENTOR Veikko K. Ketolo ATTORNEYS Jan. 24, 1967v. K. KETOLA ELECTRICALLY HEATED SAUNA INSTALLATION 2 Sheets-Sheet 2Filed Jan. 22, 1964 I NVENTOR.

AT TORN E YS United States Patent M 3,299,443 ELECTRICALLY HEATED SAUNAINSTALLATION Veikko K. Ketola, 6432 Slopes Drive, Dallas, Tex. 75231Filed Jan. 22, 1964, Ser. No. 339,478 8 Claims. (Cl. 4-160) Thisinvention relates to new and useful improvements in sauna installations,more particularly to a steam high temperature low air humidity steamproducing heating element and bathing room. This type of hot air bathhas long been know as a sauna or kivi sauna and has become popular notonly for bathing but for the therapuetic or health value attached to itsuse.

An important object of this invention is to provide an improved kivisuana bath house installation and a new and improved column type kivisauna heating unit.

A further object of the invention is to provide a sauna installationwhich can be constructed and used in residences and which is easilyserviceable and effective in operation.

A particular object of the invention is to provide an improved kivisauna heating unit or furnace which is simple in construction andeffects efficient heating and circulation of hot air and is providedwith means for quickly evaporating the water thrown on the heatingstones therein to produce the super-heated steam for the bath.

Still another object of the invention is to provide an improved kivisauna heating unit or furnace which is electrically heated and isprovided with a plurality of separated layers of stones of differentsizes to assure complete evaporation of the Water deposited on thestones without splashing and which assures that the water issufficiently spread over the stones to generate the steam promptly andeffectively without passing through the heating unit or furnace.

A particularly important object of the invention is to provide anelectrically heated kivi sauna heating unit which has a verticalcolumnar housing with imperforate side walls in the rock section,whereby steam generated by water thrown on the hot rocks is directedvertically upwardly and lateral discharge of steam is obviated, andwherein the electrical terminals of the heating elements are protectedfrom the application of steam thereto and the deteriorating action ofsteam.

Still another object of the invention is to provide a kivi sauna heatingunit or furnace which is designed to heat the rocks uniformly and todeliver steam to the room by natural air flow through the rocks in theunit, and wherein the rocks are distributed in the heating unit orfurnace with a small size rock layer at the lower end of the column anda small size rock layer on the top of the column to divide the column ofair and distribute it uniformly through the column of rock in the kivisauna heating unit; and, also, to assure that the water despositedthereon is evaporated thoroughly, the water being spread more evenlyover the heated rocks and more widespreadly dis tributed from thesmaller upper rocks to the larger rocks below for evaporation by theheat thereof.

Still another object of the invention is to provide an improved kivisauna furnace or heating unit in which the enclosed column of rocksprovides for circulation of air throughout the bathroom of the saunainstallation to more uniformly spread the heat and steam throughout theroom.

Another object of the invention is to provide a sauna bathroom in whichthe walls of the rooms are preferably formed of red wood lumber :or thelike and immediately above the kivi sauna heating unit or furnace thereis provided a heat shield or baffie to prevent damage of the ceilingportion of the room by the heated vapors from the heating unit orfurnace.

- reinforce the same and to smooth the ends thereof.

3,299,443 Patented Jan. 24, 1967 Additional objects and advantages ofthe invention will be readily apparent from the reading of the followingdescription of a device constructed in accordance with the invention,and reference to the accompanying drawings thereof, wherein:

FIGURE 1 is a fragmentary isometric view of a kivi sauna bathinstallation;

FIGURE 2 is a vertical sectional view through the kivi sauna heatingunit or furnace;

FIGURE 3 is an exploded view of the kivi sauna heating unit of furnaceshowing the elements thereof arranged in the order of their dispositionin the unit;

FIGURE 4 is a transverse sectional view through the heat shield andadjacent portion of ceiling of the kivi sauna bathroom;

FIGURE 5 is an enlarged transverse sectional View of a portion of theheat shield and mounting therefor on the ceiling as shown in FIGURE 4;and,

FIGURE 6 is an enlarged fragmentary view, partly in elevation and partlyin section, showing an electrical conductor cable passing through abushing in the wall of the kivi sauna heating unit.

In the drawings, the kivi sauna bathroom 10 is formed with walls 10a,10b and and a ceiling 18 of Wood, prefer-ably red-wood or the like, oftongue and groove style boards 11 joined together in the usual manner bynailing to suitable joists and studs. The floor 12 of the room ispreferably concreted or tiled with a drain (not shown). Mounted alongthe walls at suitable positions are plurality of benches or seats 13 foruse by the user of the room, the benches being suitably spaced from akivi sauna heating unit or furnace 15. Above the heating unit is a heatshield or insulating plate 14 formed of a sheet of aluminum metal overwhich a planar abutting relation thereto is a sheet of hard asbestos 17,said sheets being held in spaced relationship from the ceiling 18 bysuitable screws or bolts 19 extending through bushings or spacer sleeves20 into the wooden boards 11 of the ceiling. A suitable door (not shown)for entry into the room is provided in one of the walls and ispreferably located adjacent a bath or shower installation which may alsobe built at the same time that the room is built.

The walls of the room, of which the walls 10a, 10b and 100 are shown,are formed with an interior layer of the red-wood wooden boards 11 andan exterior layer of insulation 10h for preventing heat losstherethrough. Similarly a layer of insulation 1812 is provided above theceiling 18 for preventing heat loss therethrough.

The heating unit or furnace 15 includes a cylindrical housing or shell25 preferably made of stainless steel and approximately fifteen (15")inches in diameter and thirty (30") inches tall. A bead of approximatelyone-half 0/2") inch is turned in at each end of the cylinder to The endsof the cylinder are open, and a plurality of lateral apertures 28 areformed in the lower portion of the walls of the cylinder approximatelyone-fourth /4) the length thereof from the lower end. The diameter ofthe holes or apertures 28 is such that they provide approximately onehundred (100) square inches of opening from the exterior of the cylinderinto the interior thereof below the heating portion 30 thereof. Theheating section 30 of the unit has an imperforate housing wall and aplurality of vertically spaced Calrod or equivalent electrical heatingelements of the tubular type Wound into a coil and using approximatelythree thousand (3,000) watts of power each. As is shown in FIGURES 2 and3, the heating portion of the unit includes four (4) electrical heatingelements, 31, 32, 33 and 34, the uppermost element 31 being spacedapproximately five (5) inches from the upper end of the cylinder orhousing, and each of the other units 32, 33 and 34 being spaced atintervals of approximately three (3") inches below the one next above.Approximately two or three (2" or 3") inches below the lowermost heatingelement 34 is a perforated rock supporting member 35 formed of expandedmetal, woven wire or the like, preferably reinforced with a supportingring 36 defining its outer periphery and supported on a plurality ofangular bracket members 40 secured to the interior wall of thecylindrical housing at a point some two (2") inches above the uppermostedge of the apertures 28 for supporting said supporting member 35 atsuch point.

Between the supporting member 35 and the lowermost heating element 34 isdisposed a layer of rocks, preferably river rocks or rounded smooth hardgranite rocks of the type found in northern Minnesota. The dimensions ofthe rocks in the bottom layer preferably range in size from one (1")inch to one and one-half (l /2) inch in diameter. Between the lowermostheating element 3 1- and the heating element 33 next thereabove is asecond layer of rocks 46 which are larger in size than the lowermostlayer 45. The rocks of the layer 46 are of the same type as the smallerrocks but of a size ranging from one and one-fourth (1%") inches to twoand one-half (2%) inches in diameter. Between the element 33 and theelement 32 next thereabove is disposed another layer 47 of large sizerocks of approximately one and one-half (l inches to two and one-half (2/2) inches in diameter, and between the heating element 32 and theuppermost heating element 31 is a fourth layer of rocks 48, also of thesame type and size as the layer 47. Above the uppermost heating element31 is another layer 49 of large rocks, the layer being approximatelythree (3") inches in height and the rocks ranging in size from one andone-fourth (1%) inches to two and one-half (2%") inches in diameter. Ontop of the layer 49 of rocks above the upper element 31 is a top layer50 of smaller rocks ranging from one (1) inch to one and one-half (l /2)inch in diameter, and these smaller rocks are uniformly disposed overthe layer 49 of the larger rocks. It will thus be seen that thelowermost layer 45 and the uppermost layer 50 of rocks contained in thecylindrical columnar heating housing 25 are formed of small rocks Whilethe four (4) intermediate layers are formed of larger rocks, each layerof the larger rocks being disposed immediately above one of the heatingelements in the heating section of the heating unit.

This arrangement of the large rocks immediately above the heatingelements provides a large source of heat storage which is maintained inheating condition by the heating elements therebeneath. The smallerrocks provide for spreading or dispersing evenly throughout the largerrocks the water which is thrown onto the upper layer 51) of the smallrocks, and for diffusing or spreading uniformly through the larger rocksthe air which is drawn inwardly through the inlet apertures 28 andpasses upwardly through the perforate supporting member 35 into andthrough the imperforate cylindrical heating section 30 of the unit.

The heating elements are capable of producing approximately fifteenhundred degrees (1500") Fahrenheit each, and when all four (4) of theheating elements are used, twelve thousand (12,000) watts of energy areused in heating the rocks to a fifteen hundred (1500") degreesFahrenheit temperature.

In heating a sauna bathroom having approximately eight hundred forty(840) cubic feet of space therein, the energy required to heat the roomfor a period of one (1) hour starting at approximately fifty (50)degrees Fahrenheit and raising the temperature to one hundred eighty(180) Fahrenheit has been calculated to be approximately nineteenthousand (19,000) B.t.u.s, using the twelve (12) k.w. heater assemblyjust described. During the time of heating the rocks, it was found thatapproximately twenty-one thousand (21,000) B.t.u.s of energy had beenstored in the approximately one and six 4 tenths (1.6) cubic feet ofrocks comprising the heating section 30 of the heating unit. This sizeheating unit and sauna room produces a sufficient amount of energy forthree (3) of the usual separate bath applications of ap proximatelythirty 30 minutes per application.

For controlling the operation of the heating elements and producing thedesired temperature within the sauna room 10, the heating elements 31,32, 33 and 34 are connected electrically to a common source ofelectrical energy provided by cables a, 60b 60c, 60d, 60e, 60f, 60g and6011, each of which extends inwardly through a bushing or fitting 61extending through the side wall of a junction box or casing 62 securedto the exterior of the side wall of the cylindrical heater housing 25.The exterior of the wall of the housing 25 has a sheet 63 of insulatingmaterial, such as asbestos, provided with a plurality of apertures 65through which the cables extend. Each of the bushings 61 contains one ofthe wires 60a, 60b, 60c, 60d, 60c, 601, 60g or 6011, suitably extendingthrough the insulating bushing 61 into the interior of the cylindricalhousing 25 and connected to one end 60a, 60b, 60c, 60d, 60a, 60 60g or60h of one of the heating coils as best shown in FIGURE 3. The bushing61 clamps the insulating sheet 63 to the exterior of the housing 25 andthe casing 62 surrounds the fittings or bushings er and encloses thesame to protect them against heat and moisture. Also, the imperforatewall of the heating section 30 revents steam rom damaging the electricalinsulation on the cables. Electric conduit means 70, which may comprisea tubular metallic conduit of the usual heat resistant type, carries atleast one common lead from each of the heating elements and preferablyseparate leads for each of the opposite ends of the heating elements 31,32, 33, and 34 to the exterior wall of the housing of the room andthence to a switching relay box of the usual type mounted on theexterior of the building or room 10. The switching relay may includeseparate switches for each of the heating elements, if desired, or acommon switch for all, or both. From the switching relay box 75, theusual service connection extends outwardly from the building and isconnected to a source of supply of electricity of approximately twohundred eight (208) volts to two hundred forty (240) volts. Connectedwith the switching relays in the box is a thermostat having a sensingelement 91 connected by means of a conductor 02 to the thermostat. Thesensing element is disposed within the interior of the sauna bathroom 10and acts in the usual manner to control the temperature of the room bycontrolling the supply of electricity delivered to the heating elements31, 32, 33 and 34. The thermostat may be set for any desiredtemperature. All electrical wires from the relay to the heating unitsare asbestos covered copper conductors, and are preferably installed ina suitable heat insulating conduit.

In use, the several heating elements are energized by operation of theswitching relay, and after a sufficient time the heat produced by theheating elements heats the large rocks of the layers 46, 4-7, 48, and 49to an elevated temperature at which the air in the bathroom iscirculated inwardly through the apertures 28 at the bottom of thefurnace or kivi sauna heating unit and passes upwardly therethrough andis heated sufficiently to elevate the temperature in the room 10 toapproximately one hundred eighty degrees Fahrenheit.

When the room has attained a uniform temperature at the desiredelevation, the rocks having been heated to approximately five hundred(500) degrees to one thousand (1,000) degrees Fahrenheit, the userenters the room and throws a small amount of water from a pan, or dipperor the like, onto the uppermost layer of rocks 50. A half-pint of waterwill remove approximately four hundred (400) B.t.u.s of energy from therocks and introduce the heat into the room in the form of superheateddry steam. The heat thus introduced will elevate the temperature of theroom substantially and increase the relative humidity of the roomapproximately ten percent as a result of the conversion of the waterinto steam. By depositing approximately one (1) pint of water on therocks of the kivi sauna heating unit described herein, the temperatureof a room of the size mentioned would seemingly increase. While itappears to the user of the room that the temperature of the room isincreased substantially, this is merely a sensation caused by the drysuperheated steam circulated into and through the room by the unit. Itis necessary that the water be deposited on the rocks from a distance,as by use of a dipper or small pan since the superheated steam isextremely dangerous when it is produced by the water striking the hotrocks, and this steam area will be hazardous for a distance ofapproximately four (4) feet above the heating unit. For this reason, theheating unit described herein has the large circular dimension at itsupper end through which Water can be deposited .or thrown without theuser getting too close to the heating unit. It is also for this reasonthat the cylindrical wall of the heating section 3% of the housing ismade imperforate, so that there will be no lateral projection oremission of the steam produced by throwing the water on the rocks.Lateral emission of steam could result in serious injury to the occupantor user of the bathroom. It is also desirable that the water be thrownon the rocks in a suitable quantity to produce a large volume of steamimmediately; however, the steam produced will not be visible because theheat level is so high.

The columnar type heating unit heats the rocks uniformly, and produces alarge reservoir of heat over which water may pass to be vaporized intosuperheated steam. The smaller rocks at the upper end of the columnprovide for an even distribution of the water over the heated largerrocks therebelow, and the smaller rocks in the bottom of the columnprovide for diffusing uniformly the air entering the column through theaperture inlets and passing in an evenly distributed slow flow upwardlythrough the large rocks in the column. The larger rocks hold the heat asa heat reservoir longer than smaller rocks would, and provide a suitablereservoir for several bath applications.

The imperforate vertically disposed heating section or column alsodirects the superheated steam upwardly toward the baflie 14 mounted onthe ceiling of the room, where it is dispersed evenly throughout theroom without danger to the occupant or bather.

By using the column principle for heating the rocks and the room througha common source, economy is pro vided in heating both the rocks and thesauna room, since the sauna rom becomes heated to the proper temperatureat the same time as the rocks reach the esired elevated temperature forproducing the dry superheated steam.

The capacity of the heating unit may be varied by varying the number ofheating elements and the number of layers of larger rocks in the column.For example, the number of heating elements may be reduced to three orto two elements, each having a larger of larger rocks thereabove', withthe upper and lower layers of smaller rocks still remaining in place inthe column as described. Smaller bathrooms may thus be heated by suchsmaller heating units.

It will therefore be seen that an improved kivi sauna bath installationhas been provided which is adapted for erection in the usual residentialbuilding, and which is economical in construction and operation. It Willalso be seen that the heating element is simple and economical andproduces a large volume of heat and a large heat reservoir in theheating unit. It will also be seen that the heating elements may be usedin single elements or in combinations of two, three or four heatingelements simultaneously heating the rocks, and that the large rocks inthe central portion of the column provide a large reservoir of heatwhile the smaller rocks at the upper and lower ends of the column ofrocks in the heating section 6 of the unit provide for'uniformlydistributing the Water and the air over the heated larger rocks in thecentral portion of the column to produce a satisfactory quantity of drysuperheated steam quickly, efficiently and without danger of the user.The large open mouth at the upper end of the unit, likewise, permitsthrowing the water onto the rocks Without danger to the user. Inaddition the imperforate wall of the columnar heating section heats therocks in the column rapidly and at the same time causes circulation ofair through the heated rocks to heat the kivi sauna bathroom; and, whenwater is thrown on the rocks, such imperforate wall directs the steamgenerated by the hot rocks upwardly away from the user of the bathrooms.The structure of the heating unit also provides for heating the room tothe desired temperature at the same time the rocks are elevated to thedesired temperature for evaporation of the steam.

The foregoing description of the invention is explanatory only, andchanges in the details of the construction illustrated may be made bythose skilled in the art, within the scope of the appended claims,without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

1. In a sauna installation, the combination of an insulated walled room,a heating unit disposed in said room for generating and emitting steamin a generally vertically upward direction therein, supporting meansadapted to support the occupant while bathing mounted on the interiorwalls of said walled room, an insulating panel on the ceiling of saidWalled room directly above said heating unit and spaced from saidceiling, and means exterior to the walled room and connected with saidheating unit for cont-rolling the heat energy produced by said heatingunit; said heating unit including a substantially vertical cylindricalhousing having a plurality of electrical heating elements at verticallyspaced positions therein and operatively electrically connected withsaid control means exteriorly of said room; perforate support means insaid housing below said heating elements; a column of hard rounded rockssupported by said support means and having at each of its opposite endsa layer of rocks of approximately two (2") inches in vertical thicknessor height, said rocks of said layers ranging in size from one inch toone and one-half (l /2") inches in diameter; said column having betweensaid upper and lower end layers of rocks a body of larger rounded hardrocks of diametric dimensions ranging between one and one-quarter (1%")inches and two and one-half (2%") inches in diameter, said body oflarger rocks filling the space between the lower body of smaller rocksand the upper body of smaller rocks; said plurality of vertically spacedelectrical heating elements being disposed in said housing between saidupper and lower layers of rocks, said larger rocks in said column beingdisposed between and above each of said heating elements; said column ofrocks extending from said perforate support means to the upper end ofsaid housing; the upper end of said housing being open; and aperturemeans in the wall of said housing below said support means providing forair inlet into said housing below said column of rocks whereby the airis circulated inwardly through said apertures and upwardly through saidcolumn of rocks and out the open end of said cylindrical housing to heatsaid room, said rocks being also heated by said heating elements.

2. In a sauna installation, the combination of an insulated walled room,a heating unit disposed on the floor in said room for generating andemitting steam in a generally vertically upward direction therein,supporting means adapted to support the occupant while bathing mountedon the interior walls of said walled room, an insulating panel on theceiling of said walled room directly above said heating unit and spacedfrom said ceiling, and means exterior to the walled room and connectedwith said heating unit for controlling the heat energy produced by saidheating unit; said heating unit including a substantially verticalcylindrical housing having a plurality of electrical heating elements atvertically spaced positions therein and operatively electricallyconnected with said control means exteriorly of said room; perforatesupport means in said housing below said heating elements; a column ofhard rounded rocks supported by said support means and having at each ofits opposite ends a layer of rocks of approximately two (2") inches invertical thickness or height, said rocks of said layers ranging in sizefrom one inch to one and one-half (1" to 1 /2) inches in diameter; saidcolumn having between said upper and lower end layers of rocks a body oflarger rounded hard rocks of diametric dimensions ranging between oneand one-quarter (1%") inches and two and one-half (2%") inches indiameter, said body of larger rocks filling the space between the lowerbody of smaller rocks and the upper body of smaller rocks; saidplurality of vertically spaced electrical heating elements beingdisposed in said housing between said upper and lower layers of rocks,said larger rocks in said column being disposed between and above eachof said heating elements; said column of rocks extending from saidperforate support means to the upper end of said housing; said upper endof said housing being open; aperture means in the wall of said housingbelow said support means providing for air inlet into said housing belowsaid column of rocks whereby the air is circulated inwardly through saidaperture means and upwardly through said column of rocks and out theopen end of said cylindrical housing to heat said room, said rocks beingalso heated by said heating elements; the walls of said housing beingclosed between said aperture means and the open upper end of the housingwhereby heat and steam generated by said heating elements by waterthrown through the open upper end of said housing on said heated rocksis directed vertically upwardly out of the open end of said heatingelement and prevented from being emitted laterally therefrom.

3. In a sauna installation, the combination of an insulated walled room,a heating unit disposed in said room for generating and emitting steamin a generally vertically upward direction therein, supporting meansadapted to support the occupant of the bath while bathing mounted on theinterior walls of said walled room spaced from said heating unit, aninsulating panel secured to the ceiling of said walled room directlyabove said heating unit and spaced from said ceiling, and means exteriorto the walled room and connected with said heating unit for controllingthe heat energy produced by said heating unit; said heating unitincluding: a substantially vertical cylindrical housing havingelectrical heating means therein and operatively electrically connectedwith said control means exteriorly of said room; perforate support meansin said housing below said heating means; a column of hard rounded rockssupported by said support means and having at its opposite ends upperand lower spaced layers of rocks, each of said layers of rocks beingapproximately two (2") inches in vertical thickness or height, saidrocks of said layers ranging in size from one inch to one and one-half(1" to 1 /2) inches in diameter; said column having between said upperand lower end layers of rocks a body of larger rounded hard rocks ofdiametric dimensions ranging between one and one-quarter (1%") inchesand two and one-half (2%") inches in diameter, said body of larger rocksfilling the space between the lower body of smaller rocks and the upperbody of smaller rocks; said electrical heating means being disposed insaid housing between said upper and lower layers of rocks, said largerrocks in said column being disposed above said heating means; saidcolumn of rocks extending from said perforate support means to the upperend of said housing; said upper end of said housing being open; andaperture means in the wall of said housing below said support meansproviding for air inlet into said housing below said column of rockswhereby the air is circulated inwardly through said apertures andupwardly through said column of rocks and out the open end of saidcylindrical housing to heat said room, said rocks being also heated bysaid heating means; the walls of said housing being closed between saidaperture means and the open upper end thereof whereby heat and steamgenerated by said heating means by water thrown through the open upperend of said housing on said heated rocks is directed vertically upwardlyout of the open end of said heating element and prevented from beingemitted laterally therefrom; said means for controlling the heat energyproduced by said heating unit comprising a temperature sensitive controlmeans having a sensing element disposed in said walled room adjacent thesupporting means, and an operating member located exteriorly of saidwalled room and connected with a source of electrical energy supplyingenergy to the electrical heating means to control the heat supplied bythe heating means to the column of rocks in the heating unit inaccordance with the temperature sensed by said sensing element.

4. A heating element for a sauna installation comprising: an elongatecylindrical metallic housing having an open top; a perforate supportingmember disposed interiorly of said housing at a level of approximatelyonethird /3) the height of said housing from the bottom thereof; a layerof hard rounded rocks of a diameter size between one inch (1") and oneand one-half (l /2") inches disposed on said supporting member and of athickness or columnar height of at least two (2) inches; heating meansdisposed in said housing in abutting relationship with the upper planeof said first layer of rocks and above said first layer of rocks, asecond layer of larger hard rounded rocks supported by said first layerof rocks and engaging said heating means, said second layer of largerrocks being of a columnar height of at least three (3") inches and beingformed of rocks of a diameter size ranging from one and one-quarter(1%") inches and two and one-half (2%") inches in diameter; and an upperlayer of smaller rocks disposed above and supported by said intermediatelayer of larger rocks, said upper layer of rocks being of a diametersize ranging from one inch (1") and one and one-half (l /2") inches andof a vertical height or thickness of at least two (2") inches, the upperplane of said upper layer of rocks being disposed substantially in theplane of the open upper end of said housing; said housing having lateralinlet apertures below the perforate supporting member and lower layer ofrocks and being imperforate and closed between said inlet apertures andsaid open upper end whereby heat generated in the rocks by the heatingmeans and steam generated by throwing Water on the heated rocks throughthe upper open end of said housing is directed vertically upwardly outthe open upper end of said housing and is prevented from lateralemission from said housing; and means for connecting said heating meansto a source of electrical energy, said connecting means being disposedexteriorly of said housing and insulated from said heating means andprotected from steam generated by said unit.

5. A heating element for a sauna installation comprising: an elongatecylindrical metallic housing having an open top; a perforate supportingmember disposed i11- teriorly of said housing at a level approximatelyonethird /3) of the height of said housing; a first layer of hardrounded rocks of a diameter between one (1") inch and one and one-half 1/2) inches disposed on said supporting member said layer beingapproximately two (2") inches in vertical thickness or height; a firstheating element disposed in said housing and in abutting relationshipwith the upper plane of said first layer of rocks; a second layer oflarger hard rounded rocks supported by said first layer of rocks andengaging said first heating element, said second layer of rocks being ofa thickness or columnar height of approximately three (3) inches andbeing formed of rocks of a diameter size ranging between one andone-quarter (1%") inches and two and onehalf (2%) inches in diameter; asecond heating element disposed in said housing and abutting the planeof the upper level of said second layer of rocks; a third layer of rockssupported by said second layer of rocks and contacting said secondheating element and comprising hard rounded rocks of a size rangingbetween one and one-quarter (l /4) inches and two and onehalf (2%")inches in diameter and being approximately three 3") inches in thicknessor columnar height; a third heating element disposed within said housingand in the plane of the upper level of said third layer of rocks; afourth layer of rocks supported by said third layer of rocks andengaging said third heating element and comprising hard rounded rocks ofa size ranging between one and one-quarter (1%) inches and two andonehalf (2%") inches in diameter and being approximately three 3")inches in thickness or columnar height; a fourth heating elementdisposed within said housing and in the plane of the upper level of saidfourth layer of rocks; a fifth layer of rocks supported on the uppersurface of said fourth layer of rocks and engaging said fourth heatingelement and comprising hard rounded rocks of a size range from one andone-quarter (1%") inches to two and one-half (2%") inches in diameterand being approximately three (3) inches in thickness or columnarheight; a sixth layer of rocks supported on the upper surface of saidfifth layer of rocks, said rocks of said sixth layer being hard roundedrocks of a size range between one (1") inch and one and one-half (l /2")inches in diameter and forming a layer approximately two (2) inches invertical thickness or columnar height, the upper surface of said sixthlayer of rocks being disposed in substantially the plane of the open topof said hous ing; a plurality of lateral inlet apertures formed in saidhousing wall below said perforate supporting member for admitting airinto said housing below said column of rocks; the wall of said housingbeing closed throughout its length above said apertures and to the openupper end thereof, whereby heat generated in said unit is directedvertically upwardly therethrough and prevented from escaping laterally;and means on the exterior of said housing wall providing for connectingsaid heating elements to a source of heating energy for heating therocks.

6. A heating element for a sauna installation comprising: an elongatecylindrical metallic housing having an open top; a perforate supportingmember disposed interiorly of said housing at a level approximatelyonethird /5) the height of the housing from the bottom thereof, saidhousing being imperforate throughout its length from the supportingmember to the open upper end thereof; a column of hard rounded rocksdisposed on said supporting member and extending from said supportingmember to the open upper end of the housing,

the upper portion and lower portion of said column of rocks being formedof rocks of a diameter size range between (1) inch and one and one-half(1%") inches and the medial portion of the rocks between such upper andlower portions being composed of larger rocks of a diameter size rangebetween one and one-quarter (l /4") inches and two and one-half (2%)inches; heating means disposed in said housing in contact with saidcolumn of rocks above said lower portion of said column of rocks forheating said rocks; and means providing for entry of air into thehousing from the exterior thereof below the supporting surface.

7. A heating element for a sauna installation comprising: an elongatecylindrical metallic housing having an open top; a perforate supportingmember disposed interiorly of said housing at a level approximatelyonethird the height of the housing from the bottom thereof, said housinghaving an imperforate wall throughout its length from the supportingmember to the open top thereof; a column of hard rounded rocks disposedon said supporting member and extending from said supporting member tothe open top of said housing, said column of rocks comprising upper,medial and lower portions, said upper and lower portions being formed ofrocks of a diameter size range between one inch and one and one-halfinches, said medial portion of said column between said upper and lowerportions being composed of a plurality of layers of IOCliS of a diametersize range between one and one-quarter inches and two and onehalfinches; a plurality of horizontally disposed fiat electrical heatingelements disposed in said housing in said column of rocks beneath eachlayer of large rocks forming said medial portion of said column ofrocks, the lowermost heating element being disposed above said lowerportion of said column of rocks; means for connecting said heatingelements with a source of electrical energy for heating the column ofrocks in said housing; and means providing for entry of air into thehousing from the exterior thereof below the supporting surface carryingthe column rocks.

8. A heating element for a sauna installation comprising: an elongatecylindrical metallic housing having an open top; a perforate supportingmember disposed interiorty of said housing at a level approximatelyone-third /3) the height of the housing from the bottom thereof, saidhousing having an imperforate wall throughout its length from thesupporting member to the open top thereof having a plurality of lateralopenings formed in the wall thereof below the perforate supportingmember and providing for entry of air into the housing from the exteriorthereof below said perforate supporting member to pass throughimperforate portion of the housing and out the open top thereof; acolumn of hard rounded rocks disposed on said supporting member andextending from said supporting member to the upper open top of saidhousing, said column of rocks comprising upper, medium and lowerportions; said lower portion of said rocks being supported on saidperforate supporting member; a plurality of horizontally disposed fiatelectrical heating elements disposed in said housing in contact withsaid column of rocks between adjacent portions of said column of saidrock, one of said heating elements being disposed beneath and in contactwith the upper portion and above and in contact with the medial portion,and another of said heating elements being disposed beneath and incontact with said medial portion and above and in contact with saidlower portion of said column of rocks; and means for connecting saidheating elements with a source of electrical energy for heating thecolumn of rocks in said housing, said lateral openings and saidimperforate walls of said housing providing for entry of air into saidhousing below said column of rocks to pass through said column of rocksand out the open top of said housing, whereby steam is generated bywater thrown inwardly through the open top of the housing onto saidcolumn of heated rocks.

References Qited by the Examiner UNITED STATES PATENTS 1,686,860 10/1928Hussey 21937S 1,932,788 10/1933 Keating 4-160 2,654,018 9/1953 Sandberg219-378 2,846,692 8/1958 Baumann 4-160 3,110,797 11/1963 Vanne et a1.219-273 FOREIGN PATENTS 208,996 5/1960 Austria. 26,957 11/1954 Finland.822,220 11/1951 Germany. 108,905 11/1943 Sweden.

ANTHONY BARTIS, Primary Examiner. LAVERNE D. GEIGER, Examiner.

H. K, ARTIS, Assistant Examiner.

1. IN A SAUNA INSTALLATION, THE COMBINATION OF AN INSULATED WALLED ROOM,A HEATING UNIT DISPOSED IN SAID ROOM FOR GENERATING AND EMITTING STEAMIN A GENERALLY VERTICALLY UPWARD DIRECTION THEREIN, SUPPORTING MEANSADAPTED TO SUPPORT THE OCCUPANT WHILE BATHING MOUNTED ON THE INTERIORWALLS OF SAID WALLED ROOM, AN INSULATING PANEL ON THE CEILING OF SAIDWALLED ROOM DIRECTLY ABOVE SAID HEATING UNIT AND SPACED FROM SAIDCEILING, AND MEANS EXTERIOR TO THE WALLED ROOM AND CONNECTED WITH SAIDHEATING UNIT FOR CONTROLLING THE HEAT ENERGY PRODUCED BY SAID HEATINGUNIT; SAID HEATING UNIT INCLUDING A SUBSTANTIALLY VERTICAL CYLINDRICALHOUSING HAVING A PLURALITY OF ELECTRICAL HEATING ELEMENTS AT VERTICALLYSPACED POSITIONS THEREIN AND OPERATIVELY ELECTRICALLY CONNECTED WITHSAID CONTROL MEANS EXTERIORLY OF SAID ROOM; PERFORATE SUPPORT MEANS INSAID HOUSING BELOW SAID HEATING ELEMENTS; A COLUMN OF HARD ROUNDED ROCKSSUPPORTED BY SAID SUPPORT MEANS AND HAVING AT EACH OF ITS OPPOSITE ENDSA LAYER OF ROCKS OF APPROXIMATELY TWO (2") INCHES IN VERTICAL THICKNESSOR HEIGHT, SAID ROCKS OF SAID LAYERS RANGING IN SIZE FROM ONE INCH TOONE AND ONE-HALF (1 1/2") INCHES IN DIAMETER; SAID COLUMN HAVING BETWEENSAID UPPER AND LOWER END LAYERS OF ROCKS A BODY OF LARGER ROUNDED HARDROCKS OF DIAMETRIC DIMENSIONS RANGING BETWEEN ONE AND ONE-QUARTER (11/4") INCHES AND TWO AND ONE-HALF (2 1/2") INCHES IN DIAMETER, SAID BODYOF LARGER ROCKS FILLING THE SPACE BETWEEN THE LOWER BODY OF SMALLERROCKS AND THE UPPER BODY OF SMALLER ROCKS; SAID PLURALITY OF VERTICALLYSPACED ELECTRICAL HEATING ELEMENTS BEING DISPOSED IN SAID HOUSINGBETWEEN SAID UPPER AND LOWER LAYERS OF ROCKS, SAID LARGER ROCKS IN SAIDCOLUMN BEING DISPOSED BETWEEN AND ABOVE EACH OF SAID HEATING ELEMENTS;SAID COLUMN OF ROCKS EXTENDING FROM SAID PERFORATE SUPPORT MEANS TO THEUPPER END OF SAID HOUSING; THE UPPER END OF SAID HOUSING BEING OPEN; ANDAPERTURE MEANS IN THE WALL OF SAID HOUSING BELOW SAID SUPPORT MEANSPROVIDING FOR AIR INLET INTO SAID HOUSING BELOW SAID COLUMN OF ROCKSWHEREBY THE AIR IS CIRCULATED INWARDLY THROUGH SAID APERTURES ANDUPWARDLY THROUGH SAID COLUMN OF ROCKS AND OUT THE OPEN END OF SAIDCYLINDRICAL HOUSING TO HEAT SAID ROOM, SAID ROCKS BEING ALSO HEATED BYSAID HEATING ELEMENTS.